21212281880 has 16 divisors (see below), whose sum is σ = 47727634320. Its totient is φ = 8484912736.

The previous prime is 21212281837. The next prime is 21212281897. The reversal of 21212281880 is 8818221212.

It is a self number, because there is not a number n which added to its sum of digits gives 21212281880.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265153484 + ... + 265153563.

It is an arithmetic number, because the mean of its divisors is an integer number (2982977145).

Almost surely, 2^21212281880 is an apocalyptic number.

21212281880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212281880 is an abundant number, since it is smaller than the sum of its proper divisors (26515352440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21212281880 is a wasteful number, since it uses less digits than its factorization.

21212281880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530307058 (or 530307054 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 35.

The spelling of 21212281880 in words is "twenty-one billion, two hundred twelve million, two hundred eighty-one thousand, eight hundred eighty".